Carbazole

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable publication which meets basic scientific principles

Data source

Reference

Reference Type:

publication

Title:

Environmental Fate of Five Radiolabeled Coal Conversion By-Products Evaluated in a Laboratory Model Ecosystem

Author:

Lu P-Y, Metcarf RL, and Carlson EM

Year:

1978

Bibliographic source:

Environ Health Perspect 24, 201-208

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The distribution of various polycyclic (hetero)aromatic substances radiolabeled with tritium was determined over time (33 days) in a laboratory terrestrial-aquatic model ecosystem consisting of Sorghum leaves and salt marsh caterpillars on one side and plankton, alga, daphnia, and snail complemented with mosquito larvae and fish on the other side.

GLP compliance:

no

Type of study / information:

The amount of test compound measured as radioactivity in different environmental compartments and trophic organisms (water, alga, snail, mosquito, fish) was determined. Biotransformation intermediate products were identified. No overall mass balance could be established. The biomagnification as well as biodegradability potential were estimated.
In addition, partition coefficients and water solubility were determined using the radioactive test substances.

Test material

Test material information

Constituent 1

Reference substance name:

Carbazole

EC Number:

201-696-0

EC Name:

Carbazole

Cas Number:

86-74-8

Molecular formula:

C12H9N

IUPAC Name:

9H-carbazole

Details on test material:

- Name of test material (as cited in study report): carbazole
- 3H-labeled test substance was prepared by a modification of the method of Hilton and O'Brian (1964, J Agr. Food Chem 12, 236).
0.16 mL of T2O was mixed with P205 and BF3 gas to form an active T3PO4-BF3 complex as active medium
which was reacted with 60 mg of pure unlabeled compound.
- Analytical purity: no data
- Radiochemical purity (if radiolabelling): 99.04%
- Specific activity (if radiolabelling): 68.55 mCi/mMol
- Locations of the label (if radiolabelling): randomly labeled with tritium

Results and discussion

Any other information on results incl. tables

Tritium in the aqueous phase reached a maximum of 0.1246 ppm after 14 days and declined to 0.0433 ppm after 33 days.

 

The overall distribution and fate of tritium labeled compounds in different environmental/trophic constituents is shown in the following table (carbazole equivalents in ppm).

 

 

	Water	Alga (Oedogonium)	Snail (Physa)	Mosquito (Culex)	Fish (Gambusia)
Unextractable 3H	0.01628	0.1805	1.4977	0.9950	0.2666
Total extractable 3H	0.02140	0.2298	0.5757	0.2217	0.2273
Carbazole	0.00053	0.0231	0.0709	0.0593	0.0665
N-Methylcarbazole	-	-	0.0064	0.0437	0.0023
N-Acetylcarbazole	0.00001	0.0037	0.0442	-	0.0665
Unknown metabolites	0.00005	0.2006	0.1539	0.0493	0.0069
Polar extractables	0.00453	0.0024	0.3003	0.0694	0.1490

 

 

The parent compound carbazole amounted to 10.1% of total tritium in alga (EM = 49), to 12.3% in snail (EM = 134), to 26.8% in mosquito (EM = 112), and to 29.3% in fish (EM = 125)

 

Unextractable tritium was relatively high in all the organisms and comprised 43.9% of total tritium in alga, 72.7% in snail, 81.8% in mosquito, and 53.9% in fish.

 

In addition to N-methyl- and N-acetylcarbazole, three more metabolites could be separated in the extractable fraction by TLC (unpolar solvent, cyclohexane:aceton 90:10 v/v) which could not be identified (unknown metabolites).

 

The results indicate that carbazole is more readily degraded and less subject to biomagnifications than the other aromatic polycyclic compounds investigated in this study.

 

Using radioactive test substance, the partition coefficient was determined to be 2560 (logPow = 3.41). Water solubility at 25° C was 0.9075 mg/L.

Applicant's summary and conclusion

Conclusions:

The distribution and the fate of 3H-labeled carbazole was investigated in a laboratory terrestrial-aquatic model ecosystem consisting of Sorghum leaves, salt marsh caterpillars, plankton, alga, daphnia, snail, mosquito larvae, and fish for a complete food chain.
Tritium in the aqueous phase reached a maximum of 0.1246 ppm after 14 days and declined to 0.0433 ppm at the end of the experiment after 33 days. The parent compound carbazole amounted to 10.1% of total tritium in alga (EM = 49), to 12.3% in snail (EM = 134), to 26.8% in mosquito (EM = 112), and to 29.3% in fish (EM = 125) (EM = concentration of parent compound in the organism/concentration of parent compound in the water). Unextractable tritium was relatively high in all the organisms and comprised 43.9% of total tritium in alga, 72.7% in snail, 81.8% in mosquito, and 53.9% in fish indicating that transformation of carbazole was intense.
Results suggest that the bioaccumulation potential of native cabazole is limited.